Rock blocker



FIG. 1 is a front view of a rock blocker showing my new design;

FIG. 2 is a side view thereof;

FIG. 3 is an opposite side view thereof;

FIG. 4 is a front perspective view thereof; and,

FIG. 5 is rear view thereof.

In the drawings, the broken lines depict lettering and form no part of the claimed designed design. 

CLAIM The ornamental design for a rock blocker, as shown and described. 